This dude took her mats, clicked a button, and charged her a fee for making the potions. At that point, there is no tip. Raise your fee or shut your mouth.

A tip is optional, for going above and beyond, like if you had to go to the Crystal Pools of Kazun to imbue a weapon or something. Not for standing in town and smooshing some herb juice in to a bottle.

Unless they flew over to me, or somehow went above and beyond, then no fucking tip for you, guy who hocks your crafting skills and sets your own damned prices..
Tips are for people who craft for free if you bring them mats.

I don’t ask for or expect a tip when I craft something, but I always thank the person if they give me one. And I always tip (almost exorbitantly) – I had a rogue open six lockboxes for me the other day and tipped her 100g.